This application proposes continuance of the project "Canine Models of Hereditary Retinal Degeneration", as a national research resource for studies of hereditary retinal degenerations. The need for these canine mutants in research studies is addressed, as is the importance of maintaining them in a centralized breeding and distribution facility. Examples of research studies that will utilize the colony, and their significance, are summarized. Specific and comprehensive details of such research are not included, however, as these form part of the peer reviewed research programs (funded by ROI or other support) of those individual investigators utilizing the colony's resources. Four specific mutant strains of dog, each transmitting a different, unique gene for a well-characterized, autosomal recessive hereditary retinal degeneration (rcd1: Rod-Cone Dysplasia Type 1; prcd: Progressive Rod-Cone Degeneration; erd: Early Retinal Degeneration; cd: Cone Degeneration) together with appropriate nonaffected control dogs, will be bred, maintained and made available for approved research investigations. The progeny of these dogs will be distributed to approved research investigators either directly or by collection, processing and distribution of requested tissues. DNA from representative individuals and from informative pedigrees of each mutant strain will be preserved and made available to all approved investigators. The primary aims of this project are to ensure continued availability of the respective mutations and to promote their utilization by research investigators. Utilization will be promoted by solicitation of requests from investigators. Responses will be reviewed for scientific merit and priorized by an independent Retinal Research Resources Committee (RRRC), appointed and chaired by appropriate NEI/NIH staff. Allocation of distributable resources (such as dogs, tissues, DNA) from the colony will be according to priorities set by the RRRC. Investigators will be assisted in the development and implementation of protocols for optimal utilization of these mutants.